| Sumario: | The distribution and aflatoxigenicity of Aspergillus section Flavi isolates in 58 commercial poultry feed samplesobtained from 17 states in five agro-ecological zones (AEZs) in Nigeria were determined in order to assess thesafety of the feedswith respect to aflatoxin-producing fungi. Correlation was also performed for incidence of species,aflatoxin-producing ability of isolates in vitro, and aflatoxin (AFB1) concentrations in the feed. A total of1006 Aspergillus section Flavi isolates were obtained from 87.9% of the feed samples and identified as Aspergillusflavus, unnamed taxon SBG, Aspergillus parasiticus and Aspergillus tamarii. A. flavuswas themost prevalent (91.8%)of the isolates obtained from the feed in the AEZs while A. parasiticus had the lowest incidence (0.1%) and wasisolated only froma layer mash sample collected fromthe DS zone. About 29% of the Aspergillus isolates producedaflatoxins in maize grains at concentrations up to 440,500 ?g/kg B and 341,000 ?g/kg G aflatoxins. The incidenceof toxigenic isolates was highest (44.4%) in chick mash and lowest (19.9%) in grower mash. The population ofA. flavus in the feed had positive (r= 0.50) but non significant (p N 0.05) correlations with proportion of toxigenicisolates obtained fromthe feedwhile SBG had significant (p b 0.001) positive (r= 0.99)influence on AFB1 concentrationsin the feed. Poultry feed in Nigerian markets are therefore highly contaminated with aflatoxigenicAspergillus species and consequently, aflatoxins. This is a potential threat to the poultry industry and requires urgentintervention.
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